Generally, a microscope using a probe is called a scanning probe microscope (SPM) or a scanning X microscope (SXM) (X is a local physical quantity on a surface such as a tunneling current, a force among atoms, etc.). Its application field has spread to surface observation of metal, semiconductors, etc., and observation of the magnetic domain of a magnetic material, etc. Recently, the development of a high-density recording technique device using a SPM has become widespread.
For example, the following reference texts have been published regarding the application of a SXM to high-density magnetic recording:
(1) H. J. Mamin, P. H. Guethner, and D. Rugar, "Atomic Emission from a Gold Scanning-Tunneling-Microscope Tip," Phys. Rev. Lett., Vol. 65, No. 19, pp. 2418-2421, 5, Nov. 1990.
(2) R. C. Barrett and C. F. Quate, "Charge storage in a nitride-oxide-silicon medium by scanning capacitance microscopy," J. Appl. Phys. 70 (5), 1991, pp. 2725-2733.
(3) R. C. Barrett and C. F. Quate, "Large-scale charge storage by scanning capacitance microscopy," Ultramicroscopy 42-44 (1992), pp. 262-267.
(4) J. Moreland and P. Rice, "High-resolution tunneling-stabilized magnetic imaging and recording," APPL. Phys. Lett., 57 (3), 310, 1990, pp. 310-312.
(5) O. Watanuki, S. Tsuji et al., "Small magnetic patterns written with a scanning tunneling microscope," IEEE Trans. Magn., Vol. 27, No. 6, Nov. 1991, pp. 5289-5291.
(6) T. Ohkubo, J. Kishigami et al., "Submicron magnetizing and its detection based on the point magnetic recording concept," IEEE Trans. Magn., Vol. 27, No. 6, 1991, pp. 5286-5288.
Recently, a data recording and playback device using a proposed STM is used to perform magnetic recording on a recording medium, comprising placing a conductive tip near the surface of the magnetic recording medium, moving the relative position of the tip and the medium under a constant tunneling current, supplying the current in response to data to the coil around the tip, and generating a magnetic field. In playback, this determines the Z position of the tip with the tunnel current generated through placing the tip near the surface of the magnetic recording medium, and reads information on the magnetic recording medium using the magnetoresistance (MR) effect. For a probe of a MR sensor coated with a thin NiFe film, see for example reference (7), J. C. Sclonczewski, "Magnetic theory of very small devices (invited)," J. Appl. Phys. 67 (9), 1 May 1990, pp. 5341-5346.
This describes, for example, to place the tip comprising a magnetic material, such as Ni or Permalloy, near a vertical recording medium made of Co--Cr, to maintain this position, and to perform recording and playback, wherein a piezo element is used for position control.
Barrett et al. achieved a recording density of 50 Mb/in.sup.2, using charge traps in SiO.sub.2 between p-type Si and Si.sub.3 N.sub.4 see references (2) and (3). This method enables high-density recording, but has the disadvantage of being difficult to use to retain data due to the discharge of electric charges with the passage of time.
Forming submicron magnetic patterns with a SXM has been realized see references (4), (5), (6). With these techniques, a magnetic dot size is 400-800 nm, and this is equivalent to storage in the range from 4 to 1 Gb/6.45 sq cm (Gb/in.sup.2).
In the disclosed techniques, it has been difficult to turn the magnetized direction of the tip point in reverse at high speed, that is, to switch it at high speed. Following the proposed prior art, their switching speed is on the order of some KHz and, hence, this is the limit on data recording through achieving switching at 200-300 KHz. For the switching speed of a tip, see reference (8).
(8) K. Sueoka, K. Okuda et al., "Study of tip magnetization behavior in magnetic force microscope," J. Vac. Sci. Technol., B 9 (2), pp. 1313-1317, Mar/Apr 1991.
The configuration shown in reference (9) is applicable as a return path of magnetic fluxes:
(9) O. Watanuki, "Magnetic Flux Return Path for High-Density Vertical Recording," IBM IDB, Vol. 32, No. 8A, pp. 362-363, Jan. 1990.
In forming a magnetic pattern, a coil must be formed around the magnetic tip to change the magnetized direction of the tip see reference (5). When tip permeability is sufficiently high, it is possible for the coil to turn the magnetized direction of the tip edge in reverse, if it separates from the tip edge. In the case of a tip coated with a magnetic thin film, however, the coil must be formed near the tip edge. When winding a coil around the tip, a probe should have a predetermined length, but this causes the tip to easily sense vibration, which is not good from a mechanical point of view. This vibration has the disadvantage of making fine positioning difficult. In a magnetic recording and playback device that generates a tunneling current and with which it is desired to achieve high-density recording, vibration is a problem.